BUG #18453: --exclude-database has problems with capital letters

The following bug has been logged on the website:

Bug reference:      18453
Logged by:          Jernej Simončič
Email address:      jernej-s31+pg@simoncic.si
PostgreSQL version: 16.2
Operating system:   Windows Server 2022
Description:

I've got a database named Lidar, which I want to exclude from being dumped
with pg_dumpall. When I use the following command, the database is not
skipped:

"C:\Program Files\PostgreSQL\16\bin\pg_dumpall.exe"
--exclude-database="Lidar" -U postgres > D:\dumps\pg.dump

If I instead use --exclude-database="?idar", the database is skipped as
expected (using "lidar" instead of "Lidar" also doesn't skip the database).